1. Field of the Invention
The present invention relates to a semiconductor package used in digital optical instruments and a method of manufacturing the same, and more particularly to a semiconductor package used in digital optical instruments and a method of manufacturing the same that is capable of minimizing the size of a semiconductor package having an image sensor, which is referred to as a complementary metal oxide semiconductor (CMOS) or a charge coupled device (CCD), through the application of a wafer level package technology, thereby reducing the manufacturing costs of the semiconductor package and accomplishing production on a large scale.
2. Description of the Related Art
Recently, portable home video cameras and digital cameras have been miniaturized. Furthermore, camera units have been incorporated into portable mobile phones. As a result, subminiature and high-resolution image sensor modules have been increasingly required. Such image sensor modules are composed of semiconductor packages, which must have an increased number of pixels because consumers desire excellent color reproduction and detailed expression and which must be light, thin, short, and small in addition to high density because the image sensor modules are applied to potable mobile phones.
FIG. 1A is a perspective view of a conventional semiconductor package 300 constituting an image sensor module illustrating the front part of the conventional semiconductor package 300. The illustrated conventional semiconductor package 300 has a basic structure. Specifically, an image sensor or a light-receiving part 305 is formed on a silicon substrate, and a plurality of aluminum pads 310 are disposed around the image sensor or the light-receiving part 305. FIG. 1B is a perspective view of the conventional semiconductor package 300 illustrating the rear part of conventional semiconductor package 300.
Such a conventional semiconductor package 300 is generally applied to a camera module for mobile phones in one of three modes, such as a chip-on-board (COB) mode using a gold wire bonding technology, a chip-on-FPC (COF) mode using anisotropic conductive film (ACF) or non-conductive paste (NCP), and a chip-on-package (CSP) mode. Among the three modes, the CSP mode is widely used because the size of the semiconductor package manufactured in the CSP mode is very small, and the CSP mode is suitable for mass production.
CSP package structures and methods of manufacturing the same are well known. For example, the image sensor is mainly manufactured in a SHELL-OPC mode developed by Shellcase Ltd., which is one of the wafer level CSP modes.
FIGS. 2A, 2B, and 2C illustrate the structure of a conventional semiconductor package 350 manufactured in the above-mentioned SHELL-OPC mode. The conventional semiconductor package 350 is disclosed in International Patent Publication No. WO 99/40624. The semiconductor package 350 has a relatively thin and dense structure, which is protected from the external environment and is mechanically reinforced. A plurality of electric contacts 362 are plated along edge surfaces 364.
The contacts 362 extend onto a flat surface 366 of the semiconductor package 350 via the edge surfaces 364. Through this arrangement of the contacts 362, the flat surface 366 of the semiconductor package 350 and the edge surfaces 364 can be attached to a circuit board. The conventional semiconductor package 350 has fusion bumps 367 formed at the ends of the respective contacts 362. The fusion bumps 367 are arranged in a predetermined pattern.
FIG. 3 is a longitudinal sectional view illustrating the structure of another conventional semiconductor package 400 similar to the above-described semiconductor package. The conventional semiconductor package 400 is also disclosed in International Patent Publication No. WO 99/40624. The semiconductor package 400 includes a light-emitting unit and/or a light-receiving unit. The upper and lower surfaces of the semiconductor package 400 are formed of an electrically insulating and mechanical protecting material. At the upper surface and/or the lower surface of the semiconductor package 400 is disposed an integrated circuit die 422, a transparent protective film 407 of which transmits light and electrically insulating edge surfaces 414 of which have pads.
The conventional semiconductor package 400 has a plurality of electric contacts 432 along the edge surfaces 414. The conventional semiconductor package 400 also has a selective filter and/or a reflection-preventing coating film 445 formed at an outer adhesion surface 406 of the protective film 407.
FIG. 4 is a longitudinal sectional view illustrating the structure of another conventional semiconductor package 450, which is disclosed in International Patent Publication No. WO 01/43181. The conventional semiconductor package 450 includes a micro lens array 460 formed at a crystalline silicon substrate 462. Below the silicon substrate 462 is disposed a package layer 466, which is generally formed of glass. The package layer 466 is sealed by epoxy resin 464. Electric contacts 478 are formed along the edge of the package layer 466. Bumps 480 are normally formed by the electric contacts 478. The electric contacts 478 are connected to the silicon substrate 462 by conductive pads 482.
The conventional semiconductor package 450 is constructed such that a glass layer 494 and related spacer elements 486 are disposed on the silicon substrate 462 while being sealed by a bonding agent, such as epoxy resin 488, and therefore, a space 496 is formed between the micro lens array 460 and the glass layer 494. Preferably, the package layer 466 is transparent.
However, the structures of the above-described conventional semiconductor packages 400 and 450 are very complicated, and therefore, it is very difficult to manufacture the conventional semiconductor packages 400 and 450.
FIG. 5 is a longitudinal sectional view illustrating the structure of another conventional semiconductor package 500, which is manufactured in a mode different from the above-mentioned modes. The conventional semiconductor package 500 is disclosed in Japanese Patent Application No. 2002-274807. A transparent adhesion layer 508 is attached to a glass substrate 509 having a size corresponding to a plurality of semiconductor packages. Above the transparent adhesion layer 508 is disposed a silicon substrate 501 having a photoelectric conversion device region 502 formed at the lower surface thereof while a gap is formed between the silicon substrate 501 and the transparent adhesion layer 508. In the illustrated structure, connection wires 507 are connected to a connection pad 503 of the silicon substrate 501 in the vicinity of the lower surface of the silicon substrate 501.
After an insulation film 506, rewiring layers 511, columnar electrodes 512, a packaging film 513, and welding balls 514 are formed, the silicon substrate 501 is cut into pieces, and therefore, a plurality of semiconductor packages 500 each having the photoelectric conversion device region 502 are obtained. However, the structure of this conventional semiconductor packages 500 is very complicated, and therefore, it is very difficult to manufacture the conventional semiconductor package 500.
FIG. 6 is a longitudinal sectional view illustrating the structure of yet another conventional semiconductor package 600, which is different from the above-described conventional semiconductor packages. The conventional semiconductor package 600 is disclosed in Japanese Unexamined Patent Publication No. 2004-153260. The conventional semiconductor package 600 includes a pad electrode 611 formed on a semiconductor tip 610, a supporting plate 613 attached to the surface of the semiconductor tip 610, a via hole 617 formed from the inside surface of the semiconductor tip 610 to the outside surface of the pad electrode 611, and a columnar terminal 620 connected to the pad electrode 611 in the via hole 617.
At the columnar terminal 620 is formed a rewiring layer 621, on which a solder mask 622 is coated. A bump electrode 623 is electrically connected to the rewiring layer 621.
In the conventional semiconductor package 600 having the above-stated peculiar structure, wire breaking or deterioration of step coverage is effectively prevented, and therefore, the reliability of the conventional semiconductor package 600 having a ball grid array is increased.
However, the wavelength of light received by the above-mentioned semiconductor packages constituting the image sensor modules includes a visible spectrum, in which persons can see and recognize objects, in addition to an infrared spectrum and an ultraviolet spectrum.
For this reason, a camera module, in which the semiconductor package is mounted, has an infrared (IR) filter, by which infrared light transmissivity is decreased. Since the light in the infrared spectrum includes heat, the infrared light transmissivity is decreased and the reflexibility is increased by the IR filter, and therefore, the image sensor, which receives the light, is protected, and the transmissivity in the visible spectrum is increased.
According to the conventional art, a rectangular glass sheet is IR coated and is then cut into a plurality of IR filters, each of which is attached to the semiconductor package.
In this way, the semiconductor package is mounted to the camera module while the IR filter is separately attached to the semiconductor package according to the conventional art. That is, the conventional process is complicated, and therefore, improvement to the conventional process is required.